归并 快排 快速幂

/*
归并排序：不断将数组切分为两部分递归切分直到数组长度为1，之后逐渐有序合并
*/
#include <cstdio>
#include <iostream>
#include <cmath>
using namespace std;//归并 小-->大
void Merge(int a[], int s, int m, int e, int tmp[]) {int iter = s;int it1 = s, it2 = m+1;while(it1 <=m && it2 <= e) {if(a[it1] < a[it2]) tmp[iter++] = a[it1++];else tmp[iter++] = a[it2++];}while(it1 <= m)tmp[iter++] = a[it1++];while(it2 <= e)tmp[iter++] = a[it2++];for(int i=s; i<=e; ++i) {a[i] = tmp[i];}return;
}
void MergeSort(int a[], int s, int e, int tmp[]) {if(s < e) {int m = s + (e-s)/2;MergeSort(a, s, m, tmp);MergeSort(a, m+1, e, tmp);Merge(a, s, m, e, tmp);}return;
}
int a[] = {13, 12, 23, 5, 2, 34, 11, 34, 13};
int tmp[100];
int main() {int size = sizeof(a) / sizeof(int);MergeSort(a, 0, size-1, tmp);for(int i=0; i<size; ++i)printf("%d ", a[i]);
}

 

/*快排：主要思想，寻找切分元素之后两边分治处理
*/
#include <iostream>
#include <cstdio>
using namespace std;
const int maxn = 1e5 + 10;
int num[maxn];
int n;
inline void quik_sort(int s, int e) 
{//mid为切分元素int mid = num[s+(e-s)/2];// i 左侧指针，找到第一个不小于切分元素mid的数，i指向>=mid// j 右侧指针，找到第一个不大于切分元素mid的数，j指向<=midint i = s, j = e;while(i <= j) {while(num[i] < mid) i += 1;while(num[j] > mid) j -= 1;if(j >= i) {swap(num[i], num[j]);i += 1, j -= 1;}}//跳出后j < i, 分成两部分继续if(s < j) quik_sort(s, j);if(e > i) quik_sort(i, e);return;
}
int main() {scanf("%d", &n);for(int i=1; i<=n; ++i) scanf("%d", num+i);quik_sort(1, n);for (int i = 1; i <= n; ++i){printf("%d ", num[i]);        }return 0;
}

 

#include <cstdio>
#include <iostream>
using namespace std;
int Mod ;//将指数二进制化，也可以尝试其他进制
int quick_pow(int base, int t) {int ans = 1;while(t) {if(t & 1) {ans = (ans%Mod)*(base%Mod);
　　　　　　　ans %= Mod;}base = (base*base) % Mod;t >>= 1;}return ans;
}
int main()
{int base, t;scanf("%d %d %d", &base, &t, &Mod);printf("%d^%d mod %d=%d\n", base, t, Mod, quick_pow(base, t));return 0;
}